


Heart Sounds

by bluewindfall



Category: Ao no Exorcist | Blue Exorcist
Genre: Character Study, Spoilers for chapter 113, kind of, manga spoilers!!
Language: English
Status: Completed
Published: 2019-08-05
Updated: 2019-08-05
Packaged: 2020-08-09 23:37:55
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,322
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20125738
Author URL: https://archiveofourown.org/users/bluewindfall/pseuds/bluewindfall
Summary: Todo's description of him was kind. Lucifer meets Okumura Yukio and he sees disproportionate inadequacy.





	Heart Sounds

**Author's Note:**

> In case you didn't see the tags, this has spoilers for the manga up to chapter 113. Thanks for reading, and I hope you like it! :D

“Commander,” Todo greets, disturbing the veins of fire running along cracks in his face and his hands, “I met someone today, someone _spectacular,_” he laughs. 

He continues, gesturing avidly with his hands, telling of his meeting long into the fading hours of the afternoon.

It is the first of many mentions Lucifer begins to hear from him of an unnoticed, unremarkable boy who seems to despise himself so pitiably. 

Todo, still visibly unwell from his assimilation with Karura, converses with Lucifer often. In the midst of his pain, Lucifer listens merely with passive interest. He values the voices of his chosen ones and their eventual sacrifice. Even so, Todo’s fixation with the boy stems from their comparable circumstances; it is something Lucifer can recognize but cannot understand. 

He has lived, persisted for this long, and he has yet to find a kindred soul amongst his own kind, let alone these mortal creatures. The Baal are agonizingly unique in that way. 

That is until Todo speaks of his striking eyes, of the ethereal _blue_ flame dwelling inside him. _In his eyes_...how entrancing that must appear. 

“Who is he?” Lucifer finally asks. 

“My, what a surprise,” a pleased smile spreads across Todo’s complexion, younger by two decades since Lucifer last faced him. “Perhaps he has grasped your interest, Commander?”

“Who is he?” Lucifer repeats. 

“Okumura Yukio,” Todo begins, “fifteen years old, intermediate exorcist first class, demon pharmaceuticals teacher at the Exorcist Cram School.”

He adjusts his glasses, smile widening, “Currently...the youngest son of Satan.” 

Lucifer listens to the lilting cadence of Todo’s voice, listens to the growing irritation in Homare’s pulse rate as she stands vigilantly at his side. 

Afternoon drifts to evening and finally to morning. 

“I would like to meet him.” 

* * *

The instant he wakes from his slumber, Lucifer knows of his presence. 

It is feeble, all but indiscernible against the brilliant flame of the older one. Lucifer sees him, nonetheless. He hears the boy’s heartbeat leagues away, throbbing and quavering in distasteful fear. 

Okumura Yukio is weak. 

When Lucifer appears before him, he trembles; he is despicably mortal, with none of the beauty, the strength of their father. 

He cowers—his heart is loud, furiously loud in this space between them—he presses against the wall as Lucifer approaches. Lucifer cannot see if he is truly as Todo described, a boy so painfully hateful of himself that he is consumed by envy of his brother. All Okumura Yukio has done is back away. 

He does not dare breathe when Lucifer peers into his eyes. 

Indeed, the depths of his irises are the stunningly turbulent, keen chroma of their godly father’s. Lucifer finds the gnawing, insatiable shades of Gehenna lingering, settled flush against his doubts, his darkest desires. He is a child so conflicted with everything he is, he does not even realize he has already begun to lose his way. 

Okumura Yukio is a _boy_; young, yet disgracefully afraid of death. 

They are startlingly alike, in that manner.

“I don’t need saving,” he snaps, fury contorting his features. His defiance burns searingly hot despite his overwhelming weakness. It is an admirable quality, something Lucifer can respect. 

“Your heart,” Lucifer warns as he leaves, “is not so strong.”

* * *

He asks the newest guard, the one Homare is strangely not fond of, to repeat his offer. 

“I wish to save him,” Lucifer rasps. “Tell him that.” 

Okumura Yukio, Lucifer is certain, is the key, is his precious connection to Father. He does not deserve to suffer as he is now, ignorant and yellow, without a single speck of certainty to his darkness. 

The young guard grins with obvious pleasure, “I’d love to,” and he bows blithely, like a charade on his lips, “Commander.”

Lucifer waits and he waits more. 

Samael’s hold on the gates fails and as Yukio comes to him, everything begins to fall into place. Soon, he will see peace brought to this world. 

“I believed you would come.” 

“What is your objective?” Yukio demands. “You said you wanted me but for what?”

_Everything,_ echoes like a whisper in his mind, _for Father_. 

_I must have you_. 

“Thank you,” Lucifer acknowledges, “it was crucial that you come here of your own free will.”

_It is connected to every phenomenon in existence. It is...that which gave birth to us all. It is all of creation. _

In this wretched, profane world, only _he_ has the power to rid them of selfishness, of identity_. _All Lucifer yearns for is harmony; an end to this meaningless hardship. 

“This place is a mountain of evil,” Yukio sneers, “and I…am evil too.”

This time, he does not cower. He stands before Lucifer, one visible eye unhinged with hunger. There is a madness in the manner he speaks; though articulate, he is not the boy from before. His heart too, is quiet for the words he declares. The discrepancy is artless, unseemly. He is inscrutable, and he has lost something. 

Lucifer cannot hear his heart, but he hears the agony of his soul, tearing and uncoiling into fluted edges. He is still lost, but he has given up searching now. 

Okumura Yukio does not understand. 

He will. 

All will be cleaned of sin and agony once the peace comes. Even this one, full of jagged angles and warped desires, can be forgiven. 

* * *

“Good morning, Yukio. Did you rest well?”

He has discarded that black coat all of Samael’s playthings inevitably don and Lucifer notes that the white suits him less well. It is an unpleasant observation. 

Lucifer cannot hear his heart today either. He makes expressions of distress, of shock, of contempt but his heart is unflustered, apathetic. 

It is clear they are no longer alike. This is a boy who wishes to die; he yearns for it more than power, than the strength he lacks. 

He has sought for it, and since then, he has feared nothing. 

Yet, he remains weak. Such fearlessness cannot be welded into the strength he so desperately wants. 

“I too am weak. You said you want to be strong,” Lucifer placates, “in which case, you need to understand your condition.” 

Yukio concedes. Lucifer hears he was docile throughout Egin’s examination, taking in the advanced medical apparatuses with faintly veiled interest. 

* * *

“The results were outstanding,” Lucifer commends. 

Yukio’s delight is palpable; he is thrilled to learn his brother’s flames cannot harm him. It is a peculiar statement from this boy who shrinks away from the fire that kept him warm and alive, that never meant him any malice. 

He utters his first words of gratitude since boarding this ship and Lucifer takes it as encouragement to offer him more gifts. 

He treats Yukio as an esteemed guest, for he is; he has brought Father here. 

Lucifer does not mind that he covers his eye. The eyepatch, like many of his other gifts, must be accepted—removed—willingly, by his own choice. He takes the guns as well and the hatred in his eyes is fed, stoked. 

“Your generosity is unsettling...but I’m glad to have this weapon,” Yukio admits, a sliver of truth gilding his words. 

“Good,” Lucifer affirms, “I keep my promises.” 

Only, it seems his nature conflicts with his ambition. Who does he plan to use them against? This ship is sprawling with Yukio’s kind, not Lucifer’s. 

Lucifer offers him another choice, “You need both arms to bear Armumahel’s guns.” 

Accept us. You belong here now; piece by piece, you will become one of mine. 

The boy’s heart rate stutters, rising in anticipation. It is the sole notion that has sparked his excitement, unlike bloodlust, but nevertheless pungent. 

Father need not witness too much of this world yet. 

Lucifer retreats to his private quarters, having strained himself. 

He hears the even footfalls of the young guard—intriguing, that he was one of Yukio’s pupils—along the hallway, and then a soft whisper that is muffled. It mystifies Lucifer, that this guard speaks with a sly tongue, so much that Lucifer cannot hear the secrets he imparts. 

“Now I’ve told you. So, do what you want with it!”

Okumura Yukio’s heart beats unsteadily for several moments, settling peculiarly as the guard asks him, “Which side...are _you _on?”

Lucifer rests and he hears the quiet trickling of water, of Yukio’s laughter as he clenches his fist, tightening muscles in the arm Lucifer granted him. 

It is the sound of glee, of a pulsing intoxication. 

Something has changed. 

* * *

“...I’m just not hungry,” Yukio says cleanly, neatly. 

“Oh, too bad,” Todo admits, patience weighing his slow, unhurried heart. Since Karura, it has only slowed more, slower than Lucifer’s own. “You still won’t be honest, huh?”

“I’m freer than ever before,” Yukio replies and his blood agrees; it sings with voracious anticipation. 

Todo seems to think differently. There is no disappointment in his gaze as he leaves with one last reminder to this boy who he found so like himself. “You will understand.”

Yukio almost appears _concerned_ when he speaks of death, of a concept he cannot bear to see others suffer, yet inexplicably longs for. 

“Such a world is irrational and unjust,” Lucifer tells him. “Would you not agree?”

He does not. Lucifer can see that, and he can hear it. 

Okumura Yukio does not hate this world. He hates himself. 

* * *

The boy’s breaths are composed as he orders, “Check on it.” 

His voice is hard and cold, as empty as the poisonous crystals Lucifer gifted him. 

“Check on it with the commander.” 

Homare cautions him against it. Okumura Yukio cannot be trusted. Still, Lucifer welcomes him, gives him permission to witness his chosen ones' sacrifice. 

It is through his eyes, that Father will see. 

Pushing forward, Lucifer bids farewell to his subjects, loyal and steadfast warriors. It pains him that they must be ceded in this manner, for they are _worthy_; they deserve a place in the coming world. Lucifer does not show emotion. He must not deny their loss. 

Their hearts are unwaveringly stolid. His own must be the same. 

“The fateful time is at hand. Be patient just a little longer, Father.” Lucifer turns to meet the boy’s lonely eye, wishing he could see the other. 

Yukio’s heart constricts, falters, then accelerates. 

Lucifer hears it coincide with their father’s laughter, the chiming of the final hour.

“Did you know?” Yukio begins, “Last year, I received an invitation to a senior level conference at Vatican Headquarters.” 

Lucifer’s interest is piqued. He has never initiated conversation before. He speaks of banal things but there is a quivering potential in his muscles, bracing for something with immense expectation. 

The air in the room ripples, undulating toward him. 

His blood is agitated, kindled to life as he raises his right hand and the seal appears, sanguine and stark against his skin. 

“I signed a Contract of Morinath,” he smirks, great threads of wind rising at his feet, gathering to his arm, held aloft by the conceit lining his lips. Two kin of Azazel are invoked to his side by a faraway voice; spirits fashioned from sky and air. They flank him, crossing their weapons and none of Lucifer’s guard dares to approach. 

He is vain; he spends precious seconds telling of his own ingenuity, mocking them. 

Lucifer cannot believe his eyes. 

“And I ask you,” Okumura Yukio shouts, words carried by desperate scorn, “to destroy this airship!”

What wrath has forced this destruction upon them? 

How dare this _child_ seek to topple his empire? 

The strike of lightning tears into every intricately tuned device, sparking vicious arcs of plasma across the room as Lucifer watches their work crumble. 

The boy has the audacity to laugh; his madness grows, engorging itself on his hubris. He looks on with impassiveness, surveying the wreckage. “Well, I’m not going to die. If you think you can kill me, _then do it.”_

Lucifer meets his single eye; this time he sees through, he sees the fragile workings of this _mortal body_ and he wills it to combust, to ascend to light. 

Yukio clutches his sides, shivering, choking as Lucifer crushes his insides with a mere glance— 

The floor cracks, splinters, and exquisite, all-consuming blue rises, billowing outwards. The boy’s eye lights itself aflame. 

How elegant Lucifer thinks it truly is, now that he has finally seen it.

He barely registers Homare’s urging until pain blooms across his face. His body is wracked with aches as she pleads for him to stop, to retreat. 

The Illuminati is vast. This boy has done nothing more than shatter one of its countless supporting pillars. Lucifer’s plan has been set back, but it is not over. 

Lucifer cannot despise him. He is a mere tool, manipulated and misguided, torn into carefully bartered sections by an unkind world. The sigil on his hand is etched in blood that is not his own. Lucifer will remember this child, Okumura Yukio, this pitiful child who gave everything, not realizing what he has done to himself. 

Okumura Yukio has betrayed his home, his people, to join them. Not two, three days of discarding his integrity, he has given up his place here with the Illuminati for this act of vengeance. Trust relinquished freely is not so simply restored. He will never belong anywhere again.

It is a heavy cost, for so little achieved. 

Lucifer coughs blood as he is ushered away, escaping, but not before the descending, vibrating wings of hundreds of the Order’s helicopters reach his ears. 

Yukio is right. He will not expire until Samael’s puppets have depleted his purpose, until Father has no further use for him. 

When the time comes, Lucifer is certain he will be near. He will listen for the moment Okumura Yukio’s heart ceases to beat. 

Until then, Lucifer curses him to _live, _to suffer alone, to hate himself as he has always done. 

_We will meet again. This time, I will not fail to save you. _

**Author's Note:**

> Hello!
> 
> Thank you for reading! :D I read chapter 113 and was so excited. I really wanted to write something and this sort of happened. It's kind of short and I hardly did much more than paraphrase and summarize. XD 
> 
> All of the dialogue is directly from the manga, so none of it is mine, thank you to the wonderful translators!! :)
> 
> Also, I'd be really happy to hear what you thought about this, if you have time! It's always nice to get feedback, so please let me know if there was anything you liked or if I could do better on other parts. 
> 
> Anyway, I hope you enjoyed reading this! It was very fun to write. ^^
> 
> \- bluewindfall


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